kernel/linux.git/include/sound/rawmidi.h, branch linux-6.0.y

ALSA: rawmidi: Move lock to snd_rawmidi_substream

2022-06-20T07:36:02+00:00

Having a lock in snd_rawmidi_runtime can be a problem especially when a substream is accessed from the outside, as the runtime creation might be racy with the external calls. As a first step for hardening, move the spinlock from snd_rawmidi_runtime to snd_rawmidi_substream. This patch just replaces the lock calls, no real functional change is put yet. Link: https://lore.kernel.org/r/20220617144051.18985-3-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: rawmidi: Make internal functions local static

2022-06-20T07:36:01+00:00

__snd_rawmidi_transmit_peek() and __snd_rawmidi_transmit_ack() are never called from the outside. Let's make them local static and unexport them. Link: https://lore.kernel.org/r/20220617144051.18985-2-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: rawmidi: introduce SNDRV_RAWMIDI_IOCTL_USER_PVERSION

2021-09-23T07:26:40+00:00

The new framing mode causes the user space regression, because the alsa-lib code does not initialize the reserved space in the params structure when the device is opened. This change adds SNDRV_RAWMIDI_IOCTL_USER_PVERSION like we do for the PCM interface for the protocol acknowledgment. Cc: David Henningsson Cc: Fixes: 08fdced60ca0 ("ALSA: rawmidi: Add framing mode") BugLink: https://github.com/alsa-project/alsa-lib/issues/178 Signed-off-by: Jaroslav Kysela Link: https://lore.kernel.org/r/20210920171850.154186-1-perex@perex.cz Signed-off-by: Takashi Iwai

ALSA: rawmidi: Add framing mode

2021-05-17T14:02:44+00:00

This commit adds a new framing mode that frames all MIDI data into 32-byte frames with a timestamp. The main benefit is that we can get accurate timestamps even if userspace wakeup and processing is not immediate. Testing on a Celeron N3150 with this mode has a max jitter of 2.8 ms, compared to the in-kernel seq implementation which has a max jitter of 5 ms during idle and much worse when running scheduler stress tests in parallel. Signed-off-by: David Henningsson Reviewed-by: Jaroslav Kysela Link: https://lore.kernel.org/r/20210515071533.55332-1-coding@diwic.se Signed-off-by: Takashi Iwai

ALSA: rawmidi: Fix racy buffer resize under concurrent accesses

2020-05-07T20:29:14+00:00

The rawmidi core allows user to resize the runtime buffer via ioctl, and this may lead to UAF when performed during concurrent reads or writes: the read/write functions unlock the runtime lock temporarily during copying form/to user-space, and that's the race window. This patch fixes the hole by introducing a reference counter for the runtime buffer read/write access and returns -EBUSY error when the resize is performed concurrently against read/write. Note that the ref count field is a simple integer instead of refcount_t here, since the all contexts accessing the buffer is basically protected with a spinlock, hence we need no expensive atomic ops. Also, note that this busy check is needed only against read / write functions, and not in receive/transmit callbacks; the race can happen only at the spinlock hole mentioned in the above, while the whole function is protected for receive / transmit callbacks. Reported-by: butt3rflyh4ck Cc: Link: https://lore.kernel.org/r/CAFcO6XMWpUVK_yzzCpp8_XP7+=oUpQvuBeCbMffEDkpe8jWrfg@mail.gmail.com Link: https://lore.kernel.org/r/s5heerw3r5z.wl-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: rawmidi: Avoid bit fields for state flags

2020-02-14T14:53:19+00:00

The rawmidi state flags (opened, append, active_sensing) are stored in bit fields that can be potentially racy when concurrently accessed without any locks. Although the current code should be fine, there is also no any real benefit by keeping the bitfields for this kind of short number of members. This patch changes those bit fields flags to the simple bool fields. There should be no size increase of the snd_rawmidi_substream by this change. Reported-by: syzbot+576cc007eb9f2c968200@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/20200214111316.26939-4-tiwai@suse.de Signed-off-by: Takashi Iwai

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

2019-05-30T18:26:35+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman

ALSA: rawmidi: A lightweight function to discard pending bytes

2018-10-04T18:13:17+00:00

For discarding the pending bytes on rawmidi, we process with a loop of snd_rawmidi_transmit() which is just a waste of CPU power. Implement a lightweight API function to discard the pending bytes and the proceed the ring buffer instantly, and use it instead of open codes. Signed-off-by: Takashi Iwai

ALSA: Use IS_ENABLED() in common headers

2017-05-17T05:13:04+00:00

Simplify the ifdef conditions with IS_ENABLED() macro in the common sound headers. No functional changes. Signed-off-by: Takashi Iwai

ALSA: rawmidi: Add const to snd_rawmidi_ops

2017-01-12T11:49:36+00:00

Make snd_rawmidi_substream.ops to be a const pointer to be safer and allow more optimization. The patches to constify each rawmidi ops will follow. Reviewed-by: Takashi Sakamoto Signed-off-by: Takashi Iwai